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Brain & Nervous System156 citations

Microwave irradiation affects radial-arm maze performance in the rat.

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Lai H, Horita A, Guy AW, · 1994

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Microwave radiation at cell phone-level exposures impaired rats' spatial memory by disrupting key brain neurotransmitter systems.

Plain English Summary

Summary written for general audiences

Researchers exposed rats to microwave radiation at 2450 MHz for 45 minutes, then tested their maze navigation abilities. The exposed rats showed significant memory problems, getting lost more often and struggling to learn. This suggests microwave exposure may impair brain function and spatial memory.

Why This Matters

This study represents a critical piece of evidence in understanding how radiofrequency radiation affects brain function. The exposure level used (0.6 W/kg SAR) is well within the range of what people experience from cell phones and other wireless devices during typical use. What makes this research particularly significant is that it identified specific neurochemical pathways involved in the memory impairment - this wasn't just behavioral observation but actual disruption of brain neurotransmitter systems. The fact that the memory problems could be reversed with specific drugs targeting these neurotransmitter systems provides strong evidence that the microwaves were directly affecting brain chemistry, not just causing stress or heating effects. This research adds to a growing body of evidence suggesting that our daily exposure to wireless radiation may be subtly but meaningfully affecting cognitive function.

Exposure Details

SAR
0.6 W/kg
Power Density
1 µW/m²
Source/Device
2450 MHz
Exposure Duration
45 min

Exposure Context

This study used 1 µW/m² for radio frequency:

This study used 0.6 W/kg for SAR (device absorption):

Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 1 µW/m²Extreme Concern - 1,000 uW/m2FCC Limit - 10M uW/m2Effects observed in the Slight Concern rangeFCC limit is 10,000,000x higher than this level
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 2.45 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 2.45 GHzPower lines50/60 Hz5G mm28 GHzLogarithmic scale

Study Details

The aim of this study is to investigate Microwave irradiation affects radial-arm maze performance in the rat.

After 45 min of exposure to pulsed 2450 MHz microwaves (2 microseconds pulses, 500 pps, 1 mW/cm2, av...

These data indicate that both cholinergic and endogenous opioid neurotransmitter systems in the brain are involved in the microwave-induced spatial memory deficit.

Cite This Study
Lai H, Horita A, Guy AW, (1994). Microwave irradiation affects radial-arm maze performance in the rat. Bioelectromagnetics 15(2):95-104, 1994.
Show BibTeX
@article{h_1994_microwave_irradiation_affects_radialarm_1133,
  author = {Lai H and Horita A and Guy AW and},
  title = {Microwave irradiation affects radial-arm maze performance in the rat.},
  year = {1994},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/8024608/},
}
PubMed: 8024608

Cited By (156 papers)

View all 156 citing papers on Semantic Scholar

Quick Questions About This Study

Yes, rats exposed to 2450 MHz microwave radiation for 45 minutes showed significant spatial memory problems in maze tests. They got lost more often and struggled to learn navigation tasks, indicating microwave exposure can impair brain function and working memory.
Yes, pretreatment with physostigmine (a cholinergic agonist) completely reversed the memory deficits caused by 2450 MHz microwave exposure in rats. This suggests the brain's cholinergic neurotransmitter system plays a key role in microwave-induced cognitive impairment.
Memory deficits occurred at a whole-body SAR of 0.6 W/kg from pulsed 2450 MHz microwaves. Rats exposed at this level showed impaired spatial working memory in radial-arm maze tests, demonstrating biological effects at relatively low power levels.
Yes, naltrexone (an opiate antagonist) prevented memory problems when given before 2450 MHz microwave exposure in rats. This indicates the brain's endogenous opioid system is involved in microwave-induced spatial memory deficits and cognitive impairment.
Just 45 minutes of pulsed 2450 MHz microwave exposure caused significant spatial memory deficits in rats during maze navigation tests. This relatively short exposure time demonstrates that microwave radiation can quickly impact brain function and learning ability.